TROLLS and pro-gun campaigners have hijacked an Adelaide mum's Facebook page that encourages children to hand in their toy guns and think about the dangers of weapons in the wake of the US school shooting.

Pasadena mother-of-two Sam Paior last night said she had deleted about 400 vitriolic posts from the 'Toy Gun Buy Back' Facebook page she had established to help educate children, provide support for those affected by gun violence and to share mental health support and resources.

Ms Paior said she believed many of the vitriolic posters had misunderstood her reasoning behind the event.

"We are not asking for tighter gun control in Australia," she said.

"We just want to help families who want to get rid of their toy guns.

"I have had to delete about 400 posts."

Ms Paior was forced to shut the page down and has established a replacement Facebook group for the event.

Ms Paior's idea began as a way of getting rid of toy guns in her Panorama home and encouraging her sons, Ben, 12, and Bailey, 10, to think about the dangers of weapons.

The idea quickly spread after a post on Facebook attracted attention from other parents, with the concept blossoming into a community event.